Wanna make sure I got this right, but the class attachments like the armor for the stormtroopers, that only attaches to one squad right? Or does every stormtrooper gain the bonus health?

Also while im asking questions, the deployment points for the imperials during campaigns, do i deploy like the rebels do on or adjacent to the point or is it that tile?

Yes, the attachment only applies to the one group it is attachted to.

You deploy to the one square the deployment zone is and if that square is occupied to deploy to the nearest available space

Also, when your group with attachments is destroyed the attachments can be recycled the next time an appropriate group is deployed. Arc Blasters are rude. lol